DGT is an inexpensive plastic device, which can be deployed directly in waters, sediments and soils. The plastic housing holds a membrane filter, a diffusive gel layer and a binding gel layer. During deployment the chosen analytes, such as metals, nutrients or organic compounds accumulate in a controlled way on the binding layer. They can be analysed when the device is returned to the laboratory. The accumulated amount of each analyte is then used to calculate its concentration in the water, sediment or soil.
As many different types of binding layers are available, DGT can be used to measure a wide range of compounds using the same simple device, which for waters and soils, is disposable.
A consequence of the intense research and development on DGT products for more than 20 years is that its properties have been exhaustively evaluated and tested in more than 600 publications. There is a well-developed theory for a wide range of applications and there is a book on the theory and use of DGT.
DGT is technically a passive sampler, but it has much wider uses. As well as measuring concentration, DGT can be used (i) as a chemical speciation tool, (ii) to provide images of concentrations in the porewaters of sediments and soils in 2-dimensions at very high spatial resolution, and (iii) to predict bioavailability.
This web site provides supportive information for understanding and using DGT and its sister technique of DET.